In her third book chronicling the history of the Great Plains through the impact of a particular animal (following The Buffalo Hunters and The Cattlemen), Mari Sandoz recounts the trade in beaver pelts from its 17th-century beginnings along the St. Lawrence River to the last great rendezvous of traders and trappers on Ham's Fork, in what is now Wyoming, in 1834. All of Sandoz's work—her tales of the Nebraska frontier, her Great Plains histories, and her landmark biography Crazy Horse—are suffused with the harsh beauty of the land and its people, and led the Nebraska Library Association to establish the Mari Sandoz Award after her death in 1966.

"This book is not so much a historical study as a careful and intelligently drawn portrait of a world.... [The author's] point of focus is the hunting of the beaver, but the cumulative effect of the study is much broader than the conventional historical examination. Her essential concern is ecological: the relations of living creatures with each other and with their physical world. It is this perspective, unique among chroniclers of the fur trade, that gives the book its very considerable value.... Sandoz's treatment of the Indian role is a good deal more complete than most studies; her sources include Indian documentation as well as the more conventional white man's documentation."—Colorado Magazine